If It appears that the server you are on is currently blacklisted, this was most likely not caused by you but by another user of the shared server you are on.

The administrators have contacted the entity responsible for the blacklisting to de-list the server, unfortunately this process can take some time, in my experience on average it can take 5-7 days however in some rare cases it can take longer.

In the meantime as a temporary workaround you can use your email programs such as Outlook or Apple Mail with your Internet Service Provider's ( mail.bigpond.com.au, mail.optusnet.com.au ) outgoing mail servers. 

We apologise for any inconvenience caused.  

Please change your outgoing mail server to use your ISP SMTP server. 

A list of these can be found at:http://www.homepagecentre.com/hosting-guide/171/outgoing-smtp-mail-servers-of-major-australian-isps.html

They all use port 25 with no SSL and no authentication.